As teen, is lithium a safe treatment for bipolar i disorder?

Safe: Common and safe treatment.

Lithium: One of oldest mood stabilizers, is well studied & results documents. Is safe if lithium blood levels are closely monitored, along with routine checks on blood count, electrolytes & heart & kidney functions.

Yes, but an OD risk: Lithium is one of, if not the most effective med treatment for bipolar disorder. It is however a medication that can be easily overdosed and therefore when using in teens, this should be taken into account.

Another caveat: One addition to the thoughtful answers here is that lithium does take a toll on your body over the years. Frequent targets are the kidneys and the thyroid system. On the flip side, many on lithium are symptom free for decades. As stated, these trade-offs should be discussed with the prescribing psychiatrist.

Lithium: As stated above, close monitoring is essential, with blood levels.